Gen 4Regirock (NU Analysis)

he of many honks

Regirock is arguably the best tank in NU and inarguably one of the easiest Pokemon to fit on a team. Every serious NU team needs to be able to set up Stealth Rock and check Charizard and Tauros, and Regirock is an excellent choice for all three of those jobs. It also innately checks most other offensive Pokemon that don't have a super effective STAB move thanks to its remarkable bulk and respectable offensive presence. On top of that, it has access to Explosion, ensuring it will almost always at least trade one-for-one and preventing it from draining its team's momentum the way other defensive Pokemon sometimes do. Its only real flaw is its lack of a reliable recovery move, which makes it fairly easy to wear down, especially since it's often expected to counter multiple opposing Pokemon per match. That said, Regirock is a rock-solid pick for just about any team.

* Very reliable pivot and SR setter that fits well on just about any offensive or balanced team.
* Easily switches in on common threats like Charizard and Tauros and sets up SR.
* STAB Stone Edge is fairly powerful, making it dangerous for offensive Pokemon to switch in
* Earthquake has great coverage and is a more accurate option for finishing weakened Pokemon off
* Thunder Wave is always useful, especially on teams that use slow wallbreakers
* Explosion prevents momentum loss and ensures Regirock almost always at least trades 1-for-1.

[ADDITIONAL SET COMMENTS]

* Can go with Rock Slide over Stone Edge if you're using Thunder Wave for the paraflinch chance and more attacking PP.
* Leftovers is a generally great item for a bulky pivot like Regirock
* Custap Berry allows Regirock to get an emergency SR or Explosion off and is fairly easy to activate given Regirock's excellent bulk
* Lum Berry is mainly for if you want to use Regirock as a lead, allowing it to dodge sleep from Jynx/Venomoth
* EVs are very flexible
* The listed spread hits a few neat benchmarks: 252 HP makes it very unlikely for CB Tauros EQ to 2HKO after SR and Leftovers, 144+ Atk allows Regirock to always break 252 HP Poliwrath's Substitutes with EQ, and 112 SpD ensures LO Charizard's Focus Blast will never OHKO after SR.
* 252 HP / 252+ Atk is perfectly valid
* Lots of potential benchmarks in between: bumping up to 180+ Atk to always 2HKO Tauros, or 52 Def to guarantee the CB Tauros never 2HKOes, or 188 SpD so LO Charizard's HP Grass almost never 2HKOes. Do what makes you happy.
* Meant for offensive-leaning teams, where it pivots in on Tauros and Fire-types, sets up SR, fires off a couple of attacks, then explodes to get a KO and bring in a sweeper for free
* Needs a teammate that can handle Ground- and Fighting-types. Slowking is a natural choice; together they make up the famous RegiKing core.
* Regirock shouldn't be your only answer to Fire-types and Tauros since they can work together to wear Regirock down due to its lack of recovery. Bring another switch-in, or at least a revenge killer.

* Going fully specially defensive makes Regirock a more reliable counter to Fire-types and makes it a great SR setter for more defensive teams.
* Competes with Cradily, which can check some of the same Pokemon and has Recover. However, Cradily's lack of resistances to Fire and Flying make it a riskier switch-in to Pokemon like Typhlosion and Dodrio, and it's more of a momentum killer since it lacks the threat of Explosion or Thunder Wave.
* Rock Slide OHKOes Charizard and 2HKOes other Fire-types
* Toxic is the best way to damage switch-ins and fits well on stall teams
* Thunder Wave is still a good choice on balanced teams and combos well with Rock Slide to paraflinch.
* Protect stalls for Leftovers recovery and Toxic damage, scouts Choice item users, and punishes Medicham using High Jump Kick
* Explosion OHKOes most of the metagame despite the lack of Attack investment and prevents things like Poliwrath and Whiscash from setting up

[ADDITIONAL SET COMMENTS]

* Can go with Stone Edge + Earthquake make Regirock less reliant on Explosion to deal damage
* Can use Rest with cleric support to continue countering its targets throughout the match
* If Regirock is your only good answer to Tauros, you can add 52 Def EVs to ensure CB Earthquake never 2HKOes after SR.
* Wish support helps Regirock stay healthy since it lacks recovery. Lickilicky is the best Wish user but shares a Fighting weakness. Hypno and Gardevoir are the other notable users.
* Cleric support from Lickilicky, Vileplume, Meganium, or Grumpig helps, especially if using Rest.
* Needs a teammate that can handle Ground- and Fighting-types, especially if you don't carry Explosion. Slowking is a great choice. Defensive Ghost-types like Sableye and Dusclops are also good and as a bonus they block spin to keep Regirock's SR up.
* Regirock shouldn't be your only answer to Fire-types and Tauros since they can work together to wear Regirock down due to its lack of recovery. Bring another switch-in, or at least a revenge killer.

* Regirock can be surprisingly effective offensively. Decently powerful and fast after a boost, and difficult to revenge kill thanks to its great natural bulk, can lure and KO a wall with Explosion.
* Faces competition from Rhydon, who has STAB on Earthquake and hits significantly harder overall. However, Regirock has a much easier time setting up and is also much harder to revenge kill due to its greater bulk, lack of 4x weaknesses, and ability to outspeed some Choice Scarf users after a boost.
* Switch in on the same Pokemon that defensive sets would and boost.
* Stone Edge and Earthquake together have perfect coverage.
* Explosion allows Regirock to take out a fat Pokemon that it couldn't otherwise KO, like Sandslash or Poliwrath
* Ice Punch is an alternative to hit Ground-types hard without sacrificing Regirock, especially Gligar.

[ADDITIONAL SET COMMENTS]

* Jolly outspeeds Scarf Gardevoir, Medicham, and Magmortar after a boost. Adamant has a much better chance to 2HKO walls like Cradily and Slowking.
* Needs a teammate that can handle Ground- and Fighting-types. Slowking is a pretty cool choice.

* The best mid-game Sunny Day user for dedicated Sun teams
* Reliably sets up both SR and Sunny Day, then Explodes to get out of the way for a sweeper to come in safely
* Checks Fire-types that try to use your sun against you, like Scarf Typhlosion
* You don't really want to use Stone Edge very often, but it's good to have the option available for turns when setting up sun or exploding don't make sense, like if sun is up for one more turn and you need to burn a turn before refreshing it.

[ADDITIONAL SET COMMENTS]

* Max HP for enough bulk to reliably set up, max Attack to basically guarantee Explosion KOes its target and to power up Stone Edge.
* You can shift some or all of the Atk into SpD to make it even easier for Regirock to set up both SR and Sunny Day, but keep in mind that this Regirock really only wants to survive for 3 turns so it can set up SR, then Sunny Day, then Boom.
* Experts recommend that you use this set on a Sunny Day team.
* Victreebel and Shiftry are by far the two most dangerous Chlorophyll sweepers, and every dedicated sun team should carry at least one, preferably both.
* A Scarf Fire-type is also a good choice for sun teams since they benefit from the sun's power boost to Fire-type moves but can also potentially clean late-game even if you aren't able to keep the sun up. Scarf Typhlosion in particular is a good fit.
* This set is not a good lead since it's slow and therefore vulnerable to Taunt and sleep shutting it down. Faster Pokemon like Persian and Jumpluff are better Sunny Day leads. Ideally, Regirock should come in when the first batch of sunlight fades, although you can also have your lead pivot directly to Regirock instead if necessary.
* Lickilicky, Skuntank, and Hypno are some other good Sunny Day supporters.

* Defensive Ground-types (Sandslash, Gligar, Quagsire)
* Whiscash
* Fighting-types (Hitmonchan, Poliwrath)
* Defensive Ghost-types (Dusclops, Sableye)
* Grass-types with recovery (Cradily, Meganium, Vileplume)
* Like any other Pokemon, Regirock can be forced out by faster Pokemon with super effective STAB moves, but unlike most other Pokemon it needs to be weakened first or it can survive the hit and cripple its assailant.
* If all else fails, you can of course kill Regirock by using a super effective STAB move from a Pokemon with good offensive stats holding a boosting item. Specs Magneton's Flash Cannon or CB Medicham's High Jump Kick, for example.
* Just kidding. It survives both of those. Get Regirekt.

I think Regirock should be called a Tauros and Charizard / Fire-type check instead of a counter to them. Regirock has to trade or to switch back against the former if it eats an EQ on the switch, and even if it wins the 1v1 it still sacrifices a big amount of health, making it unable to check anything else afterwards. I think one shouldn't solely rely on Regirock to deal with Fire-type since it's easy to wear down and it only really checks standard 3 attacks Zard, everything else can invalidate it with Focus Blast, SunnyBeam, boosted Energy Ball... Overall, Dodrio, Skuntank and maybe Drifblim are the only threats I can think of that are countered by Regirock.

You mention Xatu as a Wish passer to help SpD Regi, but is Defensive Xatu even a thing ? I doubt it's relevant enough to appear here as a whole Pokemon, and I can't think of any reason of why you would use it for such a task, even as an offensive Wisher.

I'm not sure if Rock Polish deserves its own due to obvious competition with Rhydon and Golem, which both sports an higher Attack stat, a precious STAB on EQ and movepool advantages like Megahorn in Rhydon's case (although it trades this with Explosion). I don't think that the surprise value, the better defensive typing and bulk and the slighty better Speed ( is it necessary to outspeed Scarf Gardevoir ?) Makes it worth using over the other two. If you're going to keep it at least talk about the competition for such a role.

I think Sunny Day might deserves it's own set due to the viability of these teams in NU and the fact that most Regirock analyses in future generations also include it. Curse + 3 attack too maybe since it's a very good lure.

In the C&C section maybe talk about frail mons that struggle to switch on the offensive oruented variant but threat with their STAB like Shiftry, Floatzel, Sharpedo...

he of many honks

I guess I can change the wording from 'counter' to 'check', although some of your examples are wrong. SunnyBeamers and NP Ninetales don't OHKO Regirock, so it can switch in as they set up, take a hit, and OHKO back, meaning it does actually counter those sets. Nothing in the tier actually counters all Charizard sets at once, but Regirock comes as close as anything except Slowking, and countering the standard 3-attacks set is important on its own. I agree you shouldn't rely on Regirock as your only plan to deal with Fire-types though. I mentioned that in the overview but I'll add it to the first two sets as well.

Xatu can use BP to dodge Pursuit and scout switches before passing its Wishes. I've seen it at least a couple of times in recent years; I think it was a Bughouse special. I would say it's about as relevant as Flareon, which is not much, but if you're looking for a Wish passer who doesn't share the Fighting weakness and isn't murdered by Pursuit, your options are pretty thin.

Rock Polish does deserve its own set. I should definitely mention the competition with Rhydon though (RP Golem is pretty worthless since it doesn't outspeed anything more than Rhydon and is much weaker without being any bulkier). Yes, the better defensive typing, bulk, Speed are worth it, since they make Regirock actually hard to revenge kill. It outspeeds and OHKOes Scarf Gardevoir and Magneton, ties with Scarf Magmortar, takes only around 50% from Scarf Manectric/Typhlosion HP Grass. All of those easily revenge kill Rhydon, plus it's harder for Rhydon to set up to begin with. The surprise value is just a little bonus. They both have their place and I'll mention the competition, but Rhydon definitely doesn't outclass Regirock at this.

Sunny Day is a good set but I've decided not to write up pure weather support sets in general, at least for now. I'll give it its due in OO, and of course it'll be mentioned as a teammate on any Sunny Day sweepers' analyses. Curse I think is just fine in OO, I have not actually seen a Curse lure Regirock that I can remember.

I'll add a quick throwaway line about how faster Pokemon with super effective STABs can threaten Regirock, but they really don't want to. Floatzel for example is only doing like 50% with Waterfall and risks getting paralyzed in return, which is not really a good trade.

fever dream

SubPunch should be in OO, Regirock is probably one of the best users in NU considering how much he gets an opportunity to Sub up and pretty much nothing wants to face down a Regirock behind a Sub. SubPunch + Toxic and SubPunch + Explosion are both pretty potent overall.

Agree that RP definitely deserves a set, it and Rhydon are the two best users in NU. Golem shouldn't be RPing.

I would personally write up a Sunny Day set considering Regirock is the best support mon for the archetype, but I wouldn't say it's entirely needed. To put in perspective, Registeel has a Rain Dance support set since it is a cornerstone of rain teams in UU.

On the SpD set I would mention competition with Cradily, as Cradily can check a large amount of the same mons and has Recover, eliminating the need for Wish support that Regi needs.

Like ships in the night, you're passing me by

Yeah xatu isn’t relevant. I’ve used it on like one team a few NUPLs ago. It’s fine but not analysis worthy. Gardevoir is the more relevant one, despite the pursuit trap weakness. Even I’d just cut xatu out of that sentence. I’d also cut out flareon since it has abysmal synergy with regirock, stopping only like sunnybeamers... shares ground and water weakness and loses to Medicham and Hitmonchan too. Yikes. Flareon pairs better with cradily, since cradily can actually switch in to receive wishes against the waters and grounds that plague flareon. The only actually relevant wishers are licky, gard, and hypno.

Main thing I’d say now is personally I’d give CroRock a set too rather than being OO. Agree on also the Sunny Day set coming out of OO since it’s in literally every decent sun team.

he of many honks

Alright, updated with everyone's comments and added the Sunny Day set. I am gonna leave CroRock in OO since I don't think I've personally seen one since sand was banned even though I think it still looks pretty good on paper. I'm slow enough as it is at getting these analyses written up without adding more sets >_<

Like ships in the night, you're passing me by

My only question is the EVs on the "main" set. What I have typically believed to be standard is 204 HP / 148 Atk / 156 SpD not 252 HP / 144 Atk / 112 SpD. Your EVs are certainly fine and you make a point to note that other EVs work well too. Just a bit strange for me to see your current spread.

he of many honks

Bughouse As far as I know the 204 HP spread just comes from the UU analysis, which mentions Mismagius, Houndoom, and Alakazam as benchmarks that it's for. I tried a bunch of calcs but couldn't find any important NU-relevant benchmarks that 204/156 hits but 252/112 doesn't (for example, Specs Typhlosion Focus Blast has a 6.3% chance to OHKO with either spread), and the extra HP makes a noticeable difference against Tauros. If you know of anything specific that the 204 HP spread does for NU, I'm happy to include it or even use it as the main spread if it's something really important that I missed.